You may abstain from worldly pleasures or food and water. As long as you do not partake in worldly pleasures , you gain a +2 bonus to Heal skill checks. For every consecutive day that you willfully forgo food and water, you gain a +1 bonus to Heal skill checks, to a maximum of . You must have ready access to food and water for the fast to be meaningful. The bonuses from both abstinences stack. If you break either abstinence by partaking in worldly pleasures, food, or water, you must wait three days before you can gain the benefit of that abstinence again . Finally, you get a +2 bonus to Constitution checks made to resist the effects of dehydration and starvation.
If you are a Seraph, you may willfully starve yourself of blood instead of food and water. You get a +2 bonus to Will saves made to resist frenzying from thirst while purposefully fasting.
Your devotion to self-sacrifice and duty to others fills you with a righteous purpose, and by denying yourself wordy pleasures or even necessities, you can focus your entirety on helping others.